Hermann markwalder



July 1, 1924. 1,499,622

' H. MARKWALDER DISK COMMUTAIOR FOR ELECTRO MOTORS AND DYNAMOS Filed July 23 1925 In V6 for H 021m mm fiarkwalder Patented July 1, 1924.

UNITED STATES HERMANN MARKWALDER, OF W'URENLOS, SWITZERLAND.

DISK COMMUTATOR FOR ELECTRO MOTORS AND DYNAMOS.

Application filed July 23, 1923.

To all whom it may concern:

Be it known that I, HERMANN lVIARK- WALDER, a citizen of the Swiss Confederation, residing at VVurenlos, Aargau, Switzerland, have invented certain new and useful Improvements in Disk Commutators for Electro Motors and Dynamos (for which an application for patent has been filed in Switzerland on the 22nd of March/22), of which the following is a specification.

The drum commutators commonly used are difiicult to manufacture and expensive. The commutator sectors consist either of drawn, profiled electrolytic hard-copper or of a cast copper-piece, milled to form sectors. In both forms of construction the difficulty of putting the elements together demands skill in using the numerous tools and auxiliary devices which are necessary. The metal parts have to be heated, mounted on a mandrel, insulated at many points by means of insulating material as mica, micanite and the like, and successively clamped together and cooled before the subsequent treatment can begin.

Especially with small motors, dynamos and other electric revolving apparatus the expense of the manufacturing of the commutator is a main factor.

According to this invention these inconveniences are avoided in a simple manner. On a face plate of insulating material, having a hub, contact disks are radially fixed which correspond to the size and number of the rotor slots so that the commutator which is worn first may be removed from the rotor shaft after its contact pieces have worn to a determined degree, to be reversed and put on again, so that such a commutator lasts twice the time as the commonly used commutators. The very simple and cheap manufacturing of this improved disk commutator in comparison with the commonly used drum commutators is a criterion for the cost of manufacture of an electromotor.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming a part of this specification, with the understanding that while on the drawings several embodiments of the invention are disclosed, the invention is not confined to any strict conformity with the showing of the drawings,

Serial No. 653,296.

but may be embodied in any manner which does not make a material departure from the salient features of the invention.

In the drawings Fig. 1 shows in elevation partly in section a disk commutator, the rotor being without winding.

Fig. 2 is an end view of the disk commutator.

Fig. 3 shows in axial section a disk commutator with sector plates attached by means of screws.

Fig. 4 shows a form of construction of the disk commutator with sector plates cast in adapted to be used on both sides.

Fig. 5 shows in axial section a disk commutator adapted to be used on both sides, the sector plates being attached by means of screws.

Fig. 6 is a diagrammatical axial sectional view of an electric small motor comprising the disk commutator.

Fig. 7 shows in axial section a form of construction of a disk commutator with fixed hub and removable commutator disk.

011 the shaft 1 of an electromotor 2 an insulating or commutator disk 3 with hub 4 is pressed on perpendicularly to the axis of the shaft. In accordance with the number of slots of the rotor contact plates 5 standing opposite one another are fastened to the sides of the commutator disk 3. According to the size and circumference of said commutator disk 3 the contact plates 5 may be pressed together by means of bolts 6 (Fig. 1). Screws 9, as shown in Fig. 3, are provided which serve if the contact plates 5 are arranged on one side only. In accordance with the insulating material and the intensity of current to be used the commutator disk 3 and its contact plates 5 may be produced by casting (Fig. 4).

To replace a. worn side of a contact plate the hub 4L of the commutator disk 3 is re moved from the rotor shaft 1 and reversed so that the side of the contact disk which has not yet been used is turned towards the brush, whereupon the hub is fixed again on the rotor shaft 1. For certain types of motors, threads are arranged 011 one end of the hub 41 over which a separate commutator disk 3 is pushed to be pressed against the opposite flange of the hub by means of a flanged nut 12.

\ become Worn out so that the other side may 10 be used.

In testimony whereof I afiiX my signature in presence of two Witnesses.

HERMANN MARKWALDER.

Witnesses HEBMANN MARKWALDER, ALBERT MARKWALDER. 

